1. Field of the Invention
This invention relates to the field of exercise equipment and, more particularly, to a mechanism for adjusting the tilt angle of a back support cushion of a multi-purpose exercise machine.
2. Background
Exercise machines for performing a variety of different exercises have become widely popular. Such multi-purpose or multi-station exercise machines are relatively compact, but permit exercises to be performed that involve virtually all of the major muscle groups of the body. Such machines typically have a single seat from which many of the exercises are performed. The seat generally comprises separate seat and back cushions, each of which may be adjustable to accommodate different physiques and to more effectively position the body for the various exercises.
The back support cushion, which may also be used a chest support cushion for certain exercises, typically requires a broad range of adjustment. Prior art exercise machines have employed a variety of adjustments for back support cushions. These include telescoping adjustment; a single pivot below and behind the cushion as shown, for example, in U.S. Pat. No. 4,448,456; a single pivot adjustment below and behind the cushion with a loose swivel pivot at the top of the cushion; and a slotted adjustment as shown, for example, in U.S. Pat. No. 5,603,682. Prior art single pivot adjustments do not provide sufficient adjustment of the back support cushion for a leg extension exercise. The range of adjustment is inherently limited by the nature of the single pivot adjustment mechanism. Back support cushions with telescopic adjustments are more difficult to adjust because of friction and have more slop in the adjustment. A slotted adjustment, such as shown in the '682 patent, is cumbersome to adjust since the entire back support cushion must be dislodged from one slot position and moved into another.